1. Technical Field
Embodiments of the present invention generally relate to energy delivery systems and, more particularly, to a wireless energy delivery system employing spatial beam forming of radio frequency (RF) radiation.
2. Related Art
Energy harvesting for producing electricity from ambient energy can be accomplished by converting energy from a number of different forms, for example, including light energy (e.g., photovoltaic conversion of sunlight, for example, using solar cells); acoustic energy (e.g., piezoelectric conversion of sound waves or mechanical vibrations); and thermal energy (e.g., thermoelectric conversion using Seebeck effect). Electrical energy from radio frequency (RE) radiation can also be harvested. Sources of ambient RF energy may include, for example, broadband microwave band and mobile telephone base station emissions. Power can also be provided, in addition to or instead of being harvested, to a device by transmission of RE radiation. Power density measurement of such emissions reveals, however, that the power flux density (typically measured in units of milli-Watts per square centimeter or mW/cm2) is too low for most practical applications.
Embodiments of the present disclosure and their advantages are best understood by referring to the detailed description that follows. It should be appreciated that like reference numerals are used to identify like elements illustrated in one or more of the figures, in which the showings therein are for purposes of illustrating the embodiments and not for purposes of limiting them.